首页 > 代码库 > FZU 1686 神龙的难题 重复覆盖
FZU 1686 神龙的难题 重复覆盖
转换成0,1模型就好了,注意数据范围
#include <stdio.h> #include <string.h> #include <iostream> #include <algorithm> #include <vector> #include <queue> #include <set> #include <map> #include <string> #include <math.h> #include <stdlib.h> #include <time.h> #include <assert.h> using namespace std; const int MaxM = 500; const int MaxN = 500; const int maxnode = MaxM*MaxN; int K,n,m; struct DLX { int n,m,size; int U[maxnode],D[maxnode],R[maxnode],L[maxnode],Row[maxnode],Col[maxnode]; int H[MaxN],S[MaxM]; int ands,ans[MaxN]; void init(int _n,int _m) { ands=0x3f3f3f3f; n = _n; m = _m; for(int i = 0;i <= m;i++) { S[i] = 0; U[i] = D[i] = i; L[i] = i-1; R[i] = i+1; } R[m] = 0; L[0] = m; size = m; for(int i = 1;i <= n;i++) H[i] = -1; } void Link(int r,int c) { ++S[Col[++size]=c]; Row[size] = r; D[size] = D[c]; U[D[c]] = size; U[size] = c; D[c] = size; if(H[r] < 0)H[r] = L[size] = R[size] = size; else { R[size] = R[H[r]]; L[R[H[r]]] = size; L[size] = H[r]; R[H[r]] = size; } } void remove(int c) { for(int i = D[c];i != c;i = D[i]) L[R[i]] = L[i], R[L[i]] = R[i]; } void resume(int c) { for(int i = U[c];i != c;i = U[i]) L[R[i]]=R[L[i]]=i; } bool v[maxnode]; int f() { int ret = 0; for(int c = R[0];c != 0;c = R[c])v[c] = true; for(int c = R[0];c != 0;c = R[c]) if(v[c]) { ret++; v[c] = false; for(int i = D[c];i != c;i = D[i]) for(int j = R[i];j != i;j = R[j]) v[Col[j]] = false; } return ret; } void Dance(int d) { if(d+f()>=ands) return; if(R[0] == 0) {ands=min(ands,d);return;} int c = R[0]; for(int i = R[0];i != 0;i = R[i]) if(S[i] < S[c]) c = i; for(int i = D[c];i != c;i = D[i]) { remove(i); for(int j = R[i];j != i;j = R[j])remove(j); Dance(d+1); for(int j = L[i];j != i;j = L[j])resume(j); resume(i); } } }g; int mp[20][20],sa,sb,id[20][20]; int main() { while(~scanf("%d%d",&n,&m)) { int tot=0; for(int i=0;i<n;i++) { for(int j=0;j<m;j++) { scanf("%d",&mp[i][j]); if(mp[i][j]) id[i][j]=++tot; } } scanf("%d%d",&sa,&sb); g.init(n*m,tot); for(int i=0;i<n;i++) { for(int j=0;j<m;j++) { for(int ii=i,cnt=1;cnt<=sa&&ii<n;ii++,cnt++) { for(int jj=j,cnt2=1;cnt2<=sb&&jj<m;jj++,cnt2++) { if(mp[ii][jj]) { g.Link(i*m+j+1,id[ii][jj]); } } } } } g.Dance(0); printf("%d\n",g.ands); } return 0; }
FZU 1686 神龙的难题 重复覆盖
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